refactor: do some internal refactor.

source/dnode/mnode/impl/src/mndGrant.c

@@ -21,10 +21,8 @@
 
 static int32_t mndRetrieveGrant(SRpcMsg *pReq, SShowObj *pShow, SSDataBlock *pBlock, int32_t rows) {
   int32_t numOfRows = 0;
-  char   *pWrite;
   int32_t cols = 0;
   char    tmp[32];
-  char    tmp1[32];
 
   if (pShow->numOfRows < 1) {
     cols = 0;

source/libs/executor/src/executil.c

@@ -1120,6 +1120,7 @@ int32_t extractColMatchInfo(SNodeList* pNodeList, SDataBlockDescNode* pOutputNod
     }
   }
 
+  pMatchInfo->pList = pList;
   return code;
 }
 

source/libs/executor/src/scanoperator.c

@@ -3890,7 +3890,6 @@ SOperatorInfo* createSysTableScanOperatorInfo(void* readHandle, SSystemTableScan
   SScanPhysiNode* pScanNode = &pScanPhyNode->scan;
 
   SDataBlockDescNode* pDescNode = pScanNode->node.pOutputDataBlockDesc;
-  SSDataBlock*        pResBlock = createResDataBlock(pDescNode);
 
   int32_t num = 0;
   int32_t code = extractColMatchInfo(pScanNode->pScanCols, pDescNode, &num, COL_MATCH_FROM_COL_ID, &pInfo->matchInfo);
@@ -3899,7 +3898,7 @@ SOperatorInfo* createSysTableScanOperatorInfo(void* readHandle, SSystemTableScan
   pInfo->pUser = taosMemoryStrDup((void*)pUser);
   pInfo->sysInfo = pScanPhyNode->sysInfo;
   pInfo->showRewrite = pScanPhyNode->showRewrite;
-  pInfo->pRes = pResBlock;
+  pInfo->pRes = createResDataBlock(pDescNode);
   pInfo->pCondition = pScanNode->node.pConditions;
 
   initResultSizeInfo(&pOperator->resultInfo, 4096);
@@ -3922,7 +3921,7 @@ SOperatorInfo* createSysTableScanOperatorInfo(void* readHandle, SSystemTableScan
   pOperator->blocking = false;
   pOperator->status = OP_NOT_OPENED;
   pOperator->info = pInfo;
-  pOperator->exprSupp.numOfExprs = taosArrayGetSize(pResBlock->pDataBlock);
+  pOperator->exprSupp.numOfExprs = taosArrayGetSize(pInfo->pRes->pDataBlock);
   pOperator->pTaskInfo = pTaskInfo;
 
   pOperator->fpSet =